buzzed under?

i had it buzzed yesterday afternoon i went to lemon tree i told the girl and she said its not that uncommon she buzzed it with a no. 3 clip she said,>>>> its very short but not like bald, my hair really looks thinner and it looks ok up too i guess im young enough to have a crazy style , my mom almost freaked but when she saw it down she liked it, the coolest thing was i didnt have to pay for a full haircut she charged me $4 bucks for a beard trim ok laterz

i do not plan on shaving it i plan on having it buzzed the way im seeing it i will not lose length, i will still wear it down but the hair that was under this hair will be gone making it look thinner-- im not sure though plus if i do want to waer it up it might look crazy but i have seen it before on a few girls at school they did it to be cool though, not cuz they had thick hair
do you think a haircut place would do this for me or should i just have my bro-in law do it?

i have thick hair that is kinda long, my bro in law said to make my hair appear thinner to buzz the back of my head , i always wear it down so i was thinkin this made sense he said buzz it about 1/4" from the bottom up about 3 inches
good or bad idea will it make my hair look thinner????
thankyou very much >>>kar